M. Trombetta - Academia.edu (original) (raw)

Papers by M. Trombetta

Acta Biomaterialia, 2015

Advances introduced by additive manufacturing (AM) have significantly improved the control over t... more Advances introduced by additive manufacturing (AM) have significantly improved the control over the microarchitecture of scaffolds for tissue engineering. This has led to the flourishing of research works addressing the optimization of AM scaffolds microarchitecture to optimally trade-off between conflicting requirements (e.g. mechanical stiffness and porosity level). A fascinating trend concerns the integration of AM with other scaffold fabrication methods (i.e.-combined‖ AM), leading to hybrid architectures with complementary structural features. Although this innovative approach is still at its beginning, significant results have been achieved in terms of improved biological response to the scaffold, especially targeting the regeneration of complex tissues. This review paper reports the state of the art in the field of combined AM, posing the accent on recent trends, challenges, and future perspectives.

Materials science & engineering. C, Materials for biological applications, 2015

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesi... more Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material-characterized by a dense shell and a porous core-for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cell...

Tissue engineering of blood vessels is a promising strategy in regenerative medicine with a broad... more Tissue engineering of blood vessels is a promising strategy in regenerative medicine with a broad spectrum of potential applications. However, many hurdles for tissue-engineered vascular grafts, such as poor mechanical properties, thrombogenicity and cell over-growth inside the construct, need to be overcome prior to the clinical application. To surmount these shortcomings, we developed a poly-L-lactide (PLLA)/poly-ε-caprolactone (PCL) scaffold releasing heparin by a combination of electrospinning and fused deposition modeling technique. PLLA/heparin scaffolds were produced by electrospinning in tubular shape and then fused deposition modeling was used to armor the tube with a single coil of PCL on the outer layer to improve mechanical properties. Scaffolds were then seeded with human mesenchymal stem cells (hMSCs) and assayed in terms of morphology, mechanical tensile strength, cell viability and differentiation. This particular scaffold design allowed the generation of both a drug delivery system amenable to surmount thrombogenic issues and a microenvironment able to induce endothelial differentiation. At the same time, the PCL external coiling improved mechanical resistance of the microfibrous scaffold. By the combination of two notable techniques in biofabrication-electrospinning and FDM-and exploiting the biological effects of heparin, we developed an ad hoc differentiating device for hMSCs seeding, able to induce differentiation into vascular endothelium.

One contribution of 10 to a Theme Issue 'Nano-engineered bioactive interfaces'.

Physical Chemistry Chemical Physics, 2000

... However, in the case of aluminas and aluminates this band is never present alone, being gener... more ... However, in the case of aluminas and aluminates this band is never present alone, being generally associated with stronger bands in the regions near 3740 and near 3680 cm −1 . Apparently, however, in this ... 12, M. Casagrande, L. Storaro, M. Lenarda and R. Ganzerla, Appl. ...

Journal of the European Ceramic Society, 2005

The possibility of combining inorganic and organic components at the nanosize level in a single m... more The possibility of combining inorganic and organic components at the nanosize level in a single material by the sol-gel process has made possible the development of new multifunctional materials. However, the phase interaction between organic and inorganic moieties can be controlled only to a limited extent by using hydrolysis-condensation reactions of metal alkoxides. The preparation of nanostructured organic-inorganic (O/I) materials by assembling of nanobuilding blocks (nbb) allows controlling the extent of phase interaction, which in its turn governs the structure-properties relationships. A suitable method is the preparation of inorganic nanosized preformed objects exploiting the features and the reactivity of functional end-capping organic groups. We present here the synthesis of Si-and Zr-based nanobuilding blocks prepared by reacting diphenylsilanediol and Si and Zr precursors, with M-OR or M-Cl functions. The nonhydrolytic condensation between silanols and alkoxide or chloride groups has been exploited in order to obtain the Si-and Zr-based nbb. These nanosized objects have been further processed by dip coating for preparing films starting from suitable solutions. The structural characterisation of prepared nbb has been obtained using infrared and nuclear magnetic resonance techniques.

Journal of Solid State Chemistry, 2003

Homogeneous mesoporous zirconium-containing MCM-41 type silica were prepared by supramolecular te... more Homogeneous mesoporous zirconium-containing MCM-41 type silica were prepared by supramolecular templating and their textural and structural properties were studied using powder X-ray diffraction, N 2 porosimetry, atomic force microscopy, EXAFS, XPS, and UV-VIS-NIR diffuse reflectance spectroscopy. Their acid properties were also studied by using IR spectroscopy and by the use of catalytic tests such as the decomposition of isopropanol and the isomerization of 1-butene. The materials prepared show a good degree of crystallinity with a regular ordering of the pores into a hexagonal arrangement and high thermal stability. The specific surface area of the prepared materials decreases as the zirconium content rises. Zirconium atoms are in coordination 7 to 8 and located at the surface of the pores such that a high proportion of the oxygen atoms bonded to zirconium corresponds to surface non-condensed oxygen atoms. Both facts are responsible for the acid properties of the solids that show weak Br^nsted and medium strong Lewis acidity.

Journal of Sol-Gel Science and Technology, 2008

Hybrid organic–inorganic materials exhibit so versatile properties that they can be considered on... more Hybrid organic–inorganic materials exhibit so versatile properties that they can be considered one of the most interesting classes of materials for photonic applications, for the development of both passive and active devices. A synthetic route used for the preparation of nanostructured organic/inorganic (O/I) materials is the assembling of nano-building blocks (NBBs). This approach allows controlling the extent of phase interaction,

Journal of Sol-Gel Science and Technology, 2005

Diphenylsilanediol (DPDO) reacts with triethoxysilane (TREOS) in anhydrous conditions and in the ... more Diphenylsilanediol (DPDO) reacts with triethoxysilane (TREOS) in anhydrous conditions and in the presence of pyridine, to form complex mixtures of linear and cyclic condensation products which were identified by 29 Si NMR and ATR/FTIR spectroscopies. The distribution of products can be varied by modifying the reaction conditions. Spectroscopic analysis allowed to identify the optimal reagents ratio and concentration for the production of hetero-condensation products minimizing the number of residual OH groups whose presence would affect the performance of optical waveguides based on the synthesised nano building blocks.

Journal of Molecular Catalysis A: Chemical, 2001

The surface acidity of a series of commercial Süd Chemie acid-treated montmorillonite clays (K-ca... more The surface acidity of a series of commercial Süd Chemie acid-treated montmorillonite clays (K-catalysts) has been evaluated by a wide range of complementary experimental techniques. The different methods applied allow a rather complete characterisation of the surface acidity providing a complete picture of the Lewis/Brønsted acid strength/density of the surface sites. IR data show that the Brønsted sites on these catalysts are relatively weak and provide evidence for a slight increase of the strength and the density of Brønsted sites in the order K5 < K10 ∼ K20 < K30 in full agreement with the trend in iso-butene conversion, which is a measure of the strength and/or the abundancy of Brønsted sites. The apparent contradiction of these data with those obtained from the ammonia adsorption and iso-propanol conversion experiments can be explained by the structural and chemical modification of the clays upon acid treatment.

Journal of Materials Science: Materials in Medicine, 2013

Currently, one of the main drawbacks of using poly(e-caprolactone) in the biomedical and pharmace... more Currently, one of the main drawbacks of using poly(e-caprolactone) in the biomedical and pharmaceutical fields is represented by its low biodegradation rate. To overcome this limitation, electrospinning of PCL blended with a water-soluble poly(N-vinyl-2-pyrrolidone) was used to fabricate scaffolds with tunable fiber surface morphology and controllable degradation rates. Electrospun scaffolds revealed a highly immiscible blend state. The incorporated PVP phase was dispersed as inclusions within the electrospun fibers, and then easily extracted by immersing them in cell culture medium, exhibiting nanoporosity on the fiber surface. As a striking result, nanoporosity facilitated not only fiber biodegradation rates, but also improved cell attachment and spreading on the blend electrospun scaffolds. The present findings demonstrate that simultaneous electrospinning technique for PCL with water-soluble PVP provides important insights for successful tuning biodegradation rate for the PCL electrospun scaffolds but not limited to expand other high valuable biocompatible polymers for the future biomedical applications, ranging from tissue regeneration to controlled drug delivery.

Journal of Cellular and Molecular Medicine, 2010

Journal of Applied Polymer Science, 2011

A composite polymeric membrane to be used as electrolyte in polymer electrolyte membrane fuel cel... more A composite polymeric membrane to be used as electrolyte in polymer electrolyte membrane fuel cells has been prepared and characterized. The membrane is composed of an acidic polymer, sulfonated polyetheretherketone, and of basic filler, amino-diphenylsilandiol, a functionalized organically modified silane. Attenuated total reflectance (ATR)/fourier transform infrared spectroscopy (FTIR) demonstrated the occurrence of a specific interaction of the polymer ASO 3 H groups with the basic function of the filler. Such interaction reflected in reduced swelling, enhanced thermal stability, and good proton conductivity values at intermediate temperatures (r % 10 À2 S cm À1 at 100 C). V

Chemistry of Materials, 2006

The development of proton exchange membranes as electrolytes for polymer electrolyte fuel cells o... more The development of proton exchange membranes as electrolytes for polymer electrolyte fuel cells operating at intermediate temperatures has been achieved combining two approaches: the preparation of a cross-linked polymer and the formation of covalent organic/inorganic hybrids. A covalently crosslinked sulfonated polyetheretherketone with elevated degree of sulfonation (DS) 0.8) was prepared by reaction with HSO 3 Cl (SOPEEK). No degradation of PEEK was detected upon sulfonation, but only cross-linking via sulfonic groups with formation of SO 2 moieties was observed. The extent of ramification was calculated by analyzing the 1 H nuclear magnetic resonance (NMR) spectra of the products and resulted in 20% of the total amount of-SO 3 H groups present in the polymer. The solubility of the-SO 2 Cl precursor in organic solvents allowed easy carrying out of functionalization reactions in homogeneous conditions by lithiation and subsequent reaction with SiCl 4 , thus introducing covalenly linked silicon moieties (SOSiPEEK) at the ratios 1:0.25 and 1:0.50 per monomeric unit. The products were characterized by 1 H and 13 C NMR, attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry.

Applied Catalysis A: General, 2000

Alumina-pillared and double-pillared montmorillonite and saponite samples have been prepared and ... more Alumina-pillared and double-pillared montmorillonite and saponite samples have been prepared and characterised from the point of view of their thermal stability, porosity and structure. Surface acidity was studied by ammonia TPD, iso-propanol conversion and n-butene skeletal isomerisation catalysis, and by FT-IR spectroscopy of the surface hydroxy-groups, and of adsorbed acetonitrile and pivalonitrile. The data show that the alumina pillars of pillared montmorillonite carry stronger Lewis sites than those of pillared saponite. Additionally, stronger Brønsted sites are carried by the montmorillonite layers with respect to those of saponite. Finally, pillared montmorillonite is more active in converting iso-propanol. However, it is also too active in converting n-butene, so giving rise to faster coking and more extensive cracking. So, pillared saponite has a more selective behavior in converting n-butene into iso-butene.

Acta Biomaterialia, 2008

A technique for the preparation of bioglass foams for bone tissue engineering is presented. The p... more A technique for the preparation of bioglass foams for bone tissue engineering is presented. The process is based on the in situ foaming of a bioglass-loaded polyurethane foam as the intermediate step for obtaining a bioglass porous monolith, starting from sol-gel synthesized bioglass powders. The obtained foams were characterized using X-ray diffraction analysis, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy observations. The material was assessed by soaking samples in simulated body fluid and observing apatite layer formation. Diagnostic imaging taken from human patients was used to reconstruct a human bone portion, which was used to mould a tailored scaffold fabricated using the in situ foaming technique. The results confirmed that the obtained bioactive materials prepared with three-dimensional processing are promising for applications in reconstructive surgery tailored to each single patient.

Acta Biomaterialia, 2014

Advances introduced by additive manufacturing have significantly improved the ability to tailor s... more Advances introduced by additive manufacturing have significantly improved the ability to tailor scaffold architecture, enhancing the control over microstructural features. This has led to a growing interest in the development of innovative scaffold designs, as testified by the increasing amount of research activities devoted to the understanding of the correlation between topological features of scaffolds and their resulting properties, in order to find architectures capable of optimal trade-off between often conflicting requirements (such as biological and mechanical ones). The main aim of this paper is to provide a review and propose a classification of existing methodologies for scaffold design and optimization in order to address key issues and help in deciphering the complex link between design criteria and resulting scaffold properties.

Knee Surgery, Sports Traumatology, Arthroscopy, 2013

The present study evaluated the presence of stem cells in hamstring tendons from adult subjects o... more The present study evaluated the presence of stem cells in hamstring tendons from adult subjects of different ages. The aim was to isolate, characterize and expand these cells in vitro, and to evaluate whether cell activities are influenced by age. Tendon stem cells (TSCs) were isolated through magnetic sorting from the hamstring tendons of six patients. TSC percentage, morphology and clonogenic potential were evaluated, as well as the expression of specific surface markers. TSC multi-potency was also investigated as a function of age, and quantitative polimerase chain reaction was used to evaluate gene expression of TSCs cultured in suitable differentiating media. The presence of easily harvestable stem cell population within adult human hamstring tendons was demonstrated. These cells exhibit features such as clonogenicity, multi-potency and mesenchymal stem cells markers expression. The age-related variations in human TSCs affect the number of isolated cells and their self-renewal potential, while multi-potency assays are not influenced by tendon ageing, even though cells from younger individuals expressed higher levels of osteogenic and adipogenic genes, while chondrogenic genes were highly expressed in cells from older individuals. These results may open new opportunities to study TSCs to better understand tendon physiology, healing and pathological processes such as tendinopathy and degenerative age-related changes opening new frontiers in the management of tendinopathy and tendon ruptures.

Journal of Materials Science: Materials in Medicine, 2013

Currently, one of the main drawbacks of using poly(ε-caprolactone) in the biomedical and pharmace... more Currently, one of the main drawbacks of using poly(ε-caprolactone) in the biomedical and pharmaceutical fields is represented by its low biodegradation rate. To overcome this limitation, electrospinning of PCL blended with a water-soluble poly(N-vinyl-2-pyrrolidone) was used to fabricate scaffolds with tunable fiber surface morphology and controllable degradation rates. Electrospun scaffolds revealed a highly immiscible blend state. The incorporated PVP phase was dispersed as inclusions within the electrospun fibers, and then easily extracted by immersing them in cell culture medium, exhibiting nanoporosity on the fiber surface. As a striking result, nanoporosity facilitated not only fiber biodegradation rates, but also improved cell attachment and spreading on the blend electrospun scaffolds. The present findings demonstrate that simultaneous electrospinning technique for PCL with water-soluble PVP provides important insights for successful tuning biodegradation rate for the PCL electrospun scaffolds but not limited to expand other high valuable biocompatible polymers for the future biomedical applications, ranging from tissue regeneration to controlled drug delivery.

Acta Biomaterialia, 2015

Advances introduced by additive manufacturing (AM) have significantly improved the control over t... more Advances introduced by additive manufacturing (AM) have significantly improved the control over the microarchitecture of scaffolds for tissue engineering. This has led to the flourishing of research works addressing the optimization of AM scaffolds microarchitecture to optimally trade-off between conflicting requirements (e.g. mechanical stiffness and porosity level). A fascinating trend concerns the integration of AM with other scaffold fabrication methods (i.e.-combined‖ AM), leading to hybrid architectures with complementary structural features. Although this innovative approach is still at its beginning, significant results have been achieved in terms of improved biological response to the scaffold, especially targeting the regeneration of complex tissues. This review paper reports the state of the art in the field of combined AM, posing the accent on recent trends, challenges, and future perspectives.

Materials science & engineering. C, Materials for biological applications, 2015

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesi... more Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material-characterized by a dense shell and a porous core-for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cell...

Tissue engineering of blood vessels is a promising strategy in regenerative medicine with a broad... more Tissue engineering of blood vessels is a promising strategy in regenerative medicine with a broad spectrum of potential applications. However, many hurdles for tissue-engineered vascular grafts, such as poor mechanical properties, thrombogenicity and cell over-growth inside the construct, need to be overcome prior to the clinical application. To surmount these shortcomings, we developed a poly-L-lactide (PLLA)/poly-ε-caprolactone (PCL) scaffold releasing heparin by a combination of electrospinning and fused deposition modeling technique. PLLA/heparin scaffolds were produced by electrospinning in tubular shape and then fused deposition modeling was used to armor the tube with a single coil of PCL on the outer layer to improve mechanical properties. Scaffolds were then seeded with human mesenchymal stem cells (hMSCs) and assayed in terms of morphology, mechanical tensile strength, cell viability and differentiation. This particular scaffold design allowed the generation of both a drug delivery system amenable to surmount thrombogenic issues and a microenvironment able to induce endothelial differentiation. At the same time, the PCL external coiling improved mechanical resistance of the microfibrous scaffold. By the combination of two notable techniques in biofabrication-electrospinning and FDM-and exploiting the biological effects of heparin, we developed an ad hoc differentiating device for hMSCs seeding, able to induce differentiation into vascular endothelium.

One contribution of 10 to a Theme Issue 'Nano-engineered bioactive interfaces'.

Physical Chemistry Chemical Physics, 2000

... However, in the case of aluminas and aluminates this band is never present alone, being gener... more ... However, in the case of aluminas and aluminates this band is never present alone, being generally associated with stronger bands in the regions near 3740 and near 3680 cm −1 . Apparently, however, in this ... 12, M. Casagrande, L. Storaro, M. Lenarda and R. Ganzerla, Appl. ...

Journal of the European Ceramic Society, 2005

The possibility of combining inorganic and organic components at the nanosize level in a single m... more The possibility of combining inorganic and organic components at the nanosize level in a single material by the sol-gel process has made possible the development of new multifunctional materials. However, the phase interaction between organic and inorganic moieties can be controlled only to a limited extent by using hydrolysis-condensation reactions of metal alkoxides. The preparation of nanostructured organic-inorganic (O/I) materials by assembling of nanobuilding blocks (nbb) allows controlling the extent of phase interaction, which in its turn governs the structure-properties relationships. A suitable method is the preparation of inorganic nanosized preformed objects exploiting the features and the reactivity of functional end-capping organic groups. We present here the synthesis of Si-and Zr-based nanobuilding blocks prepared by reacting diphenylsilanediol and Si and Zr precursors, with M-OR or M-Cl functions. The nonhydrolytic condensation between silanols and alkoxide or chloride groups has been exploited in order to obtain the Si-and Zr-based nbb. These nanosized objects have been further processed by dip coating for preparing films starting from suitable solutions. The structural characterisation of prepared nbb has been obtained using infrared and nuclear magnetic resonance techniques.

Journal of Solid State Chemistry, 2003

Homogeneous mesoporous zirconium-containing MCM-41 type silica were prepared by supramolecular te... more Homogeneous mesoporous zirconium-containing MCM-41 type silica were prepared by supramolecular templating and their textural and structural properties were studied using powder X-ray diffraction, N 2 porosimetry, atomic force microscopy, EXAFS, XPS, and UV-VIS-NIR diffuse reflectance spectroscopy. Their acid properties were also studied by using IR spectroscopy and by the use of catalytic tests such as the decomposition of isopropanol and the isomerization of 1-butene. The materials prepared show a good degree of crystallinity with a regular ordering of the pores into a hexagonal arrangement and high thermal stability. The specific surface area of the prepared materials decreases as the zirconium content rises. Zirconium atoms are in coordination 7 to 8 and located at the surface of the pores such that a high proportion of the oxygen atoms bonded to zirconium corresponds to surface non-condensed oxygen atoms. Both facts are responsible for the acid properties of the solids that show weak Br^nsted and medium strong Lewis acidity.

Journal of Sol-Gel Science and Technology, 2008

Hybrid organic–inorganic materials exhibit so versatile properties that they can be considered on... more Hybrid organic–inorganic materials exhibit so versatile properties that they can be considered one of the most interesting classes of materials for photonic applications, for the development of both passive and active devices. A synthetic route used for the preparation of nanostructured organic/inorganic (O/I) materials is the assembling of nano-building blocks (NBBs). This approach allows controlling the extent of phase interaction,

Journal of Sol-Gel Science and Technology, 2005

Diphenylsilanediol (DPDO) reacts with triethoxysilane (TREOS) in anhydrous conditions and in the ... more Diphenylsilanediol (DPDO) reacts with triethoxysilane (TREOS) in anhydrous conditions and in the presence of pyridine, to form complex mixtures of linear and cyclic condensation products which were identified by 29 Si NMR and ATR/FTIR spectroscopies. The distribution of products can be varied by modifying the reaction conditions. Spectroscopic analysis allowed to identify the optimal reagents ratio and concentration for the production of hetero-condensation products minimizing the number of residual OH groups whose presence would affect the performance of optical waveguides based on the synthesised nano building blocks.

Journal of Molecular Catalysis A: Chemical, 2001

The surface acidity of a series of commercial Süd Chemie acid-treated montmorillonite clays (K-ca... more The surface acidity of a series of commercial Süd Chemie acid-treated montmorillonite clays (K-catalysts) has been evaluated by a wide range of complementary experimental techniques. The different methods applied allow a rather complete characterisation of the surface acidity providing a complete picture of the Lewis/Brønsted acid strength/density of the surface sites. IR data show that the Brønsted sites on these catalysts are relatively weak and provide evidence for a slight increase of the strength and the density of Brønsted sites in the order K5 < K10 ∼ K20 < K30 in full agreement with the trend in iso-butene conversion, which is a measure of the strength and/or the abundancy of Brønsted sites. The apparent contradiction of these data with those obtained from the ammonia adsorption and iso-propanol conversion experiments can be explained by the structural and chemical modification of the clays upon acid treatment.

Journal of Materials Science: Materials in Medicine, 2013

Currently, one of the main drawbacks of using poly(e-caprolactone) in the biomedical and pharmace... more Currently, one of the main drawbacks of using poly(e-caprolactone) in the biomedical and pharmaceutical fields is represented by its low biodegradation rate. To overcome this limitation, electrospinning of PCL blended with a water-soluble poly(N-vinyl-2-pyrrolidone) was used to fabricate scaffolds with tunable fiber surface morphology and controllable degradation rates. Electrospun scaffolds revealed a highly immiscible blend state. The incorporated PVP phase was dispersed as inclusions within the electrospun fibers, and then easily extracted by immersing them in cell culture medium, exhibiting nanoporosity on the fiber surface. As a striking result, nanoporosity facilitated not only fiber biodegradation rates, but also improved cell attachment and spreading on the blend electrospun scaffolds. The present findings demonstrate that simultaneous electrospinning technique for PCL with water-soluble PVP provides important insights for successful tuning biodegradation rate for the PCL electrospun scaffolds but not limited to expand other high valuable biocompatible polymers for the future biomedical applications, ranging from tissue regeneration to controlled drug delivery.

Journal of Cellular and Molecular Medicine, 2010

Journal of Applied Polymer Science, 2011

A composite polymeric membrane to be used as electrolyte in polymer electrolyte membrane fuel cel... more A composite polymeric membrane to be used as electrolyte in polymer electrolyte membrane fuel cells has been prepared and characterized. The membrane is composed of an acidic polymer, sulfonated polyetheretherketone, and of basic filler, amino-diphenylsilandiol, a functionalized organically modified silane. Attenuated total reflectance (ATR)/fourier transform infrared spectroscopy (FTIR) demonstrated the occurrence of a specific interaction of the polymer ASO 3 H groups with the basic function of the filler. Such interaction reflected in reduced swelling, enhanced thermal stability, and good proton conductivity values at intermediate temperatures (r % 10 À2 S cm À1 at 100 C). V

Chemistry of Materials, 2006

The development of proton exchange membranes as electrolytes for polymer electrolyte fuel cells o... more The development of proton exchange membranes as electrolytes for polymer electrolyte fuel cells operating at intermediate temperatures has been achieved combining two approaches: the preparation of a cross-linked polymer and the formation of covalent organic/inorganic hybrids. A covalently crosslinked sulfonated polyetheretherketone with elevated degree of sulfonation (DS) 0.8) was prepared by reaction with HSO 3 Cl (SOPEEK). No degradation of PEEK was detected upon sulfonation, but only cross-linking via sulfonic groups with formation of SO 2 moieties was observed. The extent of ramification was calculated by analyzing the 1 H nuclear magnetic resonance (NMR) spectra of the products and resulted in 20% of the total amount of-SO 3 H groups present in the polymer. The solubility of the-SO 2 Cl precursor in organic solvents allowed easy carrying out of functionalization reactions in homogeneous conditions by lithiation and subsequent reaction with SiCl 4 , thus introducing covalenly linked silicon moieties (SOSiPEEK) at the ratios 1:0.25 and 1:0.50 per monomeric unit. The products were characterized by 1 H and 13 C NMR, attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry.

Applied Catalysis A: General, 2000

Alumina-pillared and double-pillared montmorillonite and saponite samples have been prepared and ... more Alumina-pillared and double-pillared montmorillonite and saponite samples have been prepared and characterised from the point of view of their thermal stability, porosity and structure. Surface acidity was studied by ammonia TPD, iso-propanol conversion and n-butene skeletal isomerisation catalysis, and by FT-IR spectroscopy of the surface hydroxy-groups, and of adsorbed acetonitrile and pivalonitrile. The data show that the alumina pillars of pillared montmorillonite carry stronger Lewis sites than those of pillared saponite. Additionally, stronger Brønsted sites are carried by the montmorillonite layers with respect to those of saponite. Finally, pillared montmorillonite is more active in converting iso-propanol. However, it is also too active in converting n-butene, so giving rise to faster coking and more extensive cracking. So, pillared saponite has a more selective behavior in converting n-butene into iso-butene.

Acta Biomaterialia, 2008

A technique for the preparation of bioglass foams for bone tissue engineering is presented. The p... more A technique for the preparation of bioglass foams for bone tissue engineering is presented. The process is based on the in situ foaming of a bioglass-loaded polyurethane foam as the intermediate step for obtaining a bioglass porous monolith, starting from sol-gel synthesized bioglass powders. The obtained foams were characterized using X-ray diffraction analysis, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy observations. The material was assessed by soaking samples in simulated body fluid and observing apatite layer formation. Diagnostic imaging taken from human patients was used to reconstruct a human bone portion, which was used to mould a tailored scaffold fabricated using the in situ foaming technique. The results confirmed that the obtained bioactive materials prepared with three-dimensional processing are promising for applications in reconstructive surgery tailored to each single patient.

Acta Biomaterialia, 2014

Advances introduced by additive manufacturing have significantly improved the ability to tailor s... more Advances introduced by additive manufacturing have significantly improved the ability to tailor scaffold architecture, enhancing the control over microstructural features. This has led to a growing interest in the development of innovative scaffold designs, as testified by the increasing amount of research activities devoted to the understanding of the correlation between topological features of scaffolds and their resulting properties, in order to find architectures capable of optimal trade-off between often conflicting requirements (such as biological and mechanical ones). The main aim of this paper is to provide a review and propose a classification of existing methodologies for scaffold design and optimization in order to address key issues and help in deciphering the complex link between design criteria and resulting scaffold properties.

Knee Surgery, Sports Traumatology, Arthroscopy, 2013

The present study evaluated the presence of stem cells in hamstring tendons from adult subjects o... more The present study evaluated the presence of stem cells in hamstring tendons from adult subjects of different ages. The aim was to isolate, characterize and expand these cells in vitro, and to evaluate whether cell activities are influenced by age. Tendon stem cells (TSCs) were isolated through magnetic sorting from the hamstring tendons of six patients. TSC percentage, morphology and clonogenic potential were evaluated, as well as the expression of specific surface markers. TSC multi-potency was also investigated as a function of age, and quantitative polimerase chain reaction was used to evaluate gene expression of TSCs cultured in suitable differentiating media. The presence of easily harvestable stem cell population within adult human hamstring tendons was demonstrated. These cells exhibit features such as clonogenicity, multi-potency and mesenchymal stem cells markers expression. The age-related variations in human TSCs affect the number of isolated cells and their self-renewal potential, while multi-potency assays are not influenced by tendon ageing, even though cells from younger individuals expressed higher levels of osteogenic and adipogenic genes, while chondrogenic genes were highly expressed in cells from older individuals. These results may open new opportunities to study TSCs to better understand tendon physiology, healing and pathological processes such as tendinopathy and degenerative age-related changes opening new frontiers in the management of tendinopathy and tendon ruptures.

Journal of Materials Science: Materials in Medicine, 2013

Currently, one of the main drawbacks of using poly(ε-caprolactone) in the biomedical and pharmace... more Currently, one of the main drawbacks of using poly(ε-caprolactone) in the biomedical and pharmaceutical fields is represented by its low biodegradation rate. To overcome this limitation, electrospinning of PCL blended with a water-soluble poly(N-vinyl-2-pyrrolidone) was used to fabricate scaffolds with tunable fiber surface morphology and controllable degradation rates. Electrospun scaffolds revealed a highly immiscible blend state. The incorporated PVP phase was dispersed as inclusions within the electrospun fibers, and then easily extracted by immersing them in cell culture medium, exhibiting nanoporosity on the fiber surface. As a striking result, nanoporosity facilitated not only fiber biodegradation rates, but also improved cell attachment and spreading on the blend electrospun scaffolds. The present findings demonstrate that simultaneous electrospinning technique for PCL with water-soluble PVP provides important insights for successful tuning biodegradation rate for the PCL electrospun scaffolds but not limited to expand other high valuable biocompatible polymers for the future biomedical applications, ranging from tissue regeneration to controlled drug delivery.